After 400-Kilometer Human Chain, Secessionists Need to Line Up Support for Referendum

BARCELONA—Hundreds of thousands of pro-independence Catalans joined hands to form a nearly 250-mile human chain Wednesday to press their cause, but a tougher organizational challenge lies ahead in lining up support for a secession referendum.

Such a vote, pledged for 2014 by Catalonia's two leading political parties, has provoked opposition from Spain's conservative central government and revealed strains within the independence movement that seem unlikely to be resolved even by the protest's massive turnout.